The present invention relates to an arrangement for feeding fine-particle material to be separated to an electrostatic free-fall cutter.
Methods of dry separation of mixtures of fine-particle materials or minerals in a high-voltage field of an electrostatic free-fall cutter are known in the art, for example as disclosed in "Chemie-Ingenieur-Technik" 53 (1981) 9/6. These methods have high technical importance and are used in industrial production, for example for separating comminuted triboelectrically charged crude potassium salt. For obtaining good separation of valuable substance from the remaining components of the material to be separated in the electrostatic high-voltage field of a free-full cutter, it is known to break the fine-particle material which flows in free fall from the inlet to the electrostatic high-voltage field of the free-fall cutter. A supply funnel is used for this purpose, as disclosed for example in the German Pat. No. 1,174,273. The funnel has an upper inclined part which opens into a lower part limited by vertical walls, and braking inserts for example as open semi-pipes are provided in the lower part. The inserts must separate the stream of material and a great width of the material stream is obtained, so that it must flow as thin material fog into the separating device. The industrial utilization of this known supply funnel has shown, however, that is provides for a good braking action of the material to be separated, but the material to be separated is subdivided into individual streams and each stream has a different quantity of the material to be separated, so that essential variations in the flow of the material to be treated take place.